Unanswered: Sybase load database low throughput with LTO
I have the following issue:
I made a succesfull database dump directly to a HP LTO (Ultrium) tapedevice. When loading back the dump we have a very low troughput. We need 2h15min for 8GB. This is far below we expected.
We also have a dds drive connected to the machine. Both scsi.
We also tried dumping to the dds drive. The loading from dds drive is 8 times faster than from LTO ???
We use Sybase version 11.9.2 on a hp-ux 11i machine.
There are no error messages at all.
I use the following commands for the LTO:
dump database xxx to '/dev/rmt/0mn' with capacity=16777126,init
load database xxx from '/dev/rmt/0mn'
The same is used for the load from dds except for the device name of course.
The default blocksize for sybase is used.
I have checked with the option listonly=full possible differences between the dump on DDS and the dump on LTO version. There's none.
Can anybody explane:
- why the troughput of the LTO is that low?
- whether or not the performance of the LTO is affected by the blocksize?